Aging power delivery infrastructures

Aging Power Delivery Infrastructures......Page 1
Series Introduction......Page 4
Preface......Page 6
Contents......Page 9
1.1 WHAT ARE AGING POWER DELIVERY INFRASTRUCTURES?......Page 15
Characteristics of an Aging Infrastructure Area......Page 16
1.2 POWER DELIVERY, NOT POWER T&D......Page 17
The Wholesale Grid......Page 18
Power Delivery: Getting Power to the People......Page 20
1.3 THE BUSINESS ENVIRONMENT HAS CHANGED......Page 22
1.4 FOUR FACTORS CONTRIBUTE TO AGING INFRASTRUCTURE PROBLEMS......Page 25
Contributing Factor 1: Aging Equipment......Page 27
Contributing Factor 2: Obsolete System Layouts......Page 28
Configuration limitations......Page 30
Symptoms of the obsolete system layout......Page 31
N-1 criterion......Page 32
N-1's limitations......Page 33
Partial failures......Page 35
Configuration complexity......Page 36
Not well used......Page 37
An untapped resource......Page 38
It is rocket science......Page 40
Executive management's perspective: a more business-driven focus......Page 42
Changes in cultural "standards" may be needed......Page 43
1.5 CONCLUSION AND SUMMARY......Page 45
What Can Be Done......Page 47
REFERENCES......Page 48
2.1 INTRODUCTION......Page 50
2.2 T&D SYSTEM'S MISSION......Page 51
2.3 THE "LAWS OF T&D"......Page 53
Hierarchical Voltage Levels......Page 55
2.4 LEVELS OF THE T&D SYSTEM......Page 56
The Transmission Level......Page 60
The Substation Level......Page 61
The Feeder Level......Page 62
The Service Transformers......Page 65
What is Transmission and what is Distribution?......Page 66
2.5 UTILITY DISTRIBUTION EQUIPMENT......Page 67
Transmission and Distribution Lines......Page 68
Transformers......Page 69
Protection......Page 70
Capacitors......Page 71
2.6 T&D COSTS......Page 73
Substation Costs......Page 74
Feeder System Costs......Page 76
Service Level Costs......Page 77
The Cost to Upgrade Exceeds the Cost to Build......Page 78
Losses are an operating cost......Page 79
The costs of losses......Page 81
2.7 TYPES OF DELIVERY SYSTEM DESIGN......Page 83
Large-Trunk vs. Multi-Branch Feeder Layout......Page 90
Service Areas......Page 91
Dynamic Service Area Planning......Page 92
The Systems Approach......Page 93
2.8 CONCLUSION......Page 95
REFERENCES......Page 99
3.1 THE TWO Qs: QUANTITY AND QUALITY OF POWER......Page 100
3.2 ELECTRIC CONSUMER NEED FOR QUANTITY OF POWER......Page 101
Appliances Convert End Uses into Electric Load......Page 102
Consumer Class Load Curves......Page 103
Load Duration Curves......Page 106
Spatial Patterns of Electric Demand......Page 107
Spatial Patterns of Electric Demand......Page 109
Assessing Value of Quality by Studying the Cost of a Lack of It......Page 110
Value-Based Planning......Page 111
Voltage Sags Cause Momentary Interruptions......Page 112
Frequency and Duration of Interruptions Both Impact Cost......Page 114
Cost of Interruption Varies by Customer Class......Page 117
Cost of Interruption Varies as a Function of Time of Use......Page 119
Recommended Method of Application of Customer Interruption Cost Data......Page 121
Cost of Surges and Harmonics......Page 122
End-Use Modeling of Consumer Availability Needs......Page 123
3.4 Two-Q Analyses: Quantity and Quality of Power Are Both Important Aspects of Consumer Value......Page 126
3.5 CONCLUSION AND SUMMARY......Page 129
REFERENCES......Page 130
4.1 INTRODUCTION......Page 131
Extent......Page 133
Types of Interruptions......Page 134
Voltage Sags Often Look Like Interruptions......Page 136
4.3 RELIABILITY INDICES......Page 137
Momentary Interruption Index......Page 139
Analysis Using Reliability Indices......Page 140
Indirect Reliability Engineering: Contingency and Margin Criteria......Page 142
Duration Is the Most Popular Criterion......Page 143
Duration Is Equivalent to "Probability of Unavailable Power"......Page 144
Predictive Reliability Analysis Methods......Page 145
Reliability Evaluation Methods......Page 146
Application of Probabilities......Page 147
4.5 COST IS KING......Page 148
The Market Comb......Page 149
Offering Variable Levels of Reliability......Page 150
4.6 TWO-Q ANALYSIS OF POWER SYSTEMS......Page 152
4.7 CONCLUSION AND SUMMARY......Page 154
REFERENCES......Page 155
5.1 INTRODUCTION......Page 157
Types of Cost......Page 158
Embedded, Marginal, and Incremental Cost......Page 159
Decisions Based on When and How Much is Spent......Page 161
Present Worth Analysis......Page 163
Present worth analysis does not say "no" to truly essential elements of a plan......Page 165
Interest rate......Page 166
Inflation......Page 167
Earnings targets......Page 168
Planning errors......Page 169
Present Worth Factor Is a Decision- Making Tool, Not a Financial Factor......Page 170
Comprehensive Present Worth Example......Page 171
Leveled Value......Page 173
Lifetime levelized analysis......Page 175
Comparing cost over different equipment lifetimes......Page 176
Lowest Cost Among Alternatives......Page 177
Benefit/Cost Ratio Analysis......Page 178
Least-Cost Selection of Alternatives (Traditional Approach)......Page 179
Facing Budget Constraints......Page 181
Using Benefit/Cost Ratio to Make the Decisions......Page 182
Results Still Not Completely Satisfactory......Page 184
What went wrong with benefit/cost ratio prioritization?......Page 185
Marginal Benefit Cost Analysis......Page 186
Application of Marginal Benefit-Cost Evaluation......Page 187
Refurbishment alternatives receive a "marginal" advantage......Page 190
5.6 CONCLUSION......Page 191
REFERENCES......Page 192
6.1 INTRODUCTION......Page 193
6.2 INSPECTION, TESTING, AND DIAGNOSTIC EVALUATION......Page 194
Three Purposes......Page 195
Field or Laboratory Evaluation......Page 196
Non-Destructive, Destructive or Forensic Tests......Page 197
Voltage withstand and dielectric strength......Page 199
Mechanical tests......Page 200
6.3 EQUIPMENT TESTING AND DIAGNOSIS METHODS......Page 201
DC or AC?......Page 202
Power Factor Tests......Page 204
Polarization Recovery Tests......Page 206
Hi-Potential (Hi-Pot) Tests......Page 207
Partial Discharge (PD) Tests......Page 208
Oil Samples Required......Page 210
Water Content (Karl Fischer) Test......Page 211
Dielectric Breakdown Tests......Page 212
Interfacial tension tests......Page 213
Analyzing Gases Produced by Insulation Deterioration......Page 214
Dissolved gas tests......Page 215
Comparison of Tests and Diagnostic Methods......Page 216
Comparison of Tests and Diagnostic Methods......Page 217
REFERENCES......Page 218
7.1 INTRODUCTION......Page 220
7.2 EQUIPMENT AGING......Page 221
Chronological age......Page 222
Cumulative service stress......Page 223
Abnormal event stress......Page 226
Technical obsolescence......Page 229
Lack Of Proper Care Can Accelerate Aging Effects......Page 230
Loss of Life and Load-Related Lifetime......Page 231
"Old" Depends on the Expected or Design Lifetime......Page 233
Effects of Equipment Aging......Page 234
De-rating to Preserve Remaining Lifetime......Page 235
High failure rate and uncertainty make for a costly combination......Page 236
Failure time prediction: an inexact science......Page 237
Quantitative Analysis of Equipment Failure Probabilities......Page 239
Eventually the failure rates become quite high......Page 241
Example 1: A Typical Failure Rate Escalation and Its Impact on the Installed Equipment Base......Page 243
Failure-Count Diagrams......Page 245
Example 2: A More "Real World" Case......Page 246
Replacement policy analysis......Page 248
7.5 SUMMARY OF KEY POINTS......Page 249
FOR FURTHER READING......Page 250
8.1 INTRODUCTION......Page 251
Example System......Page 252
No sites available......Page 254
Financial pressure......Page 255
No additional room available at existing sites......Page 256
Incremental Mistakes and Boiled Frogs......Page 257
Poor Planning was a Major Contributor to Metropolitan Power and Light's Problems......Page 258
Forced to choose capacity over configuration......Page 259
Higher Equipment Utilization......Page 260
High utilization ratios mean more interconnection is needed......Page 262
More frequent and higher periods of equipment stress......Page 263
8.4 FEEDER SYSTEM IMPACTS......Page 264
Feeder Level Reliability......Page 265
Non-optimal feeder getaways and routes......Page 266
Non-optimal routing......Page 267
Duct crowding/exposure......Page 268
Using the Feeder System to Mitigate Problems Caused by Substation-Level Outages......Page 269
8.5 The Concept of Feeder System "Strength"......Page 272
Loss of Contingency Reach Due to Obsolete System Layout......Page 274
Feeder Problems Often Don't Get the "Respect" They Are Due......Page 277
Improved Communication with Community and Regulators......Page 278
Compact Substation Designs......Page 279
Improved long-range planning......Page 280
8.7 SUMMARY OF KEY POINTS......Page 281
REFERENCES......Page 282
9.1 INTRODUCTION......Page 283
The N-1 Criterion......Page 284
The base case......Page 285
Relaxation of design standards for contingencies......Page 286
Application of N-1 using a Computer Program......Page 287
Supposedly Good Systems Begin Giving Bad Results......Page 289
9.3 LIMITATIONS OF N-1 METHODOLOGY......Page 290
Utilization Ratio Sensitivity......Page 291
Traditional utilization levels......Page 292
Higher utilization rates......Page 293
Contingency support neighborhood......Page 295
Traditional power systems had "small" contingency support neighborhoods......Page 297
Systems with high utilization rates have larger contingency support neighborhoods......Page 298
High Utilization Coupled With Aging System Equipment Leads to Greatly Increased Service Problems......Page 300
The Result: Lack of Dependability as Sole Planning Tools......Page 301
Partial Failures......Page 303
Aging and High Utilization Systems Are More Sensitive to Load Forecasting Errors......Page 304
Weather normalization......Page 305
Impact of Mistakes in Weather Normalization on Reliability......Page 306
Spatial forecasting......Page 308
Impact of spatial forecast errors on reliability......Page 310
Interconnection Complexity......Page 311
9.5 THE PROBLEM IS NOT HIGH UTILIZATION RATES......Page 312
Traditional Tools Have Shortcomings With Respect to Modern Needs......Page 313
Explicit Reliability-Based Engineering Methods......Page 314
REFERENCES......Page 316
10.1 INTRODUCTION......Page 318
10.2 DISTRIBUTION PLANNING AND THE PERCEIVED ROLE OF DISTRIBUTION......Page 319
Distribution Can Be Asked To Do A Lot More......Page 321
A Quantum Difference in "Bang for the Buck"......Page 323
Good Distribution Planning Is Rocket Science......Page 324
Feeder System Strength......Page 325
The Systems Approach......Page 326
10.3 FLEXIBILITY AND EFFECTIVENESS IN FEEDER LEVEL PLANNING......Page 329
Multiple Switches Divide Each Feeder into "Switch Zones"......Page 331
Voltage, Loading Criteria, and Line Upgrades for Feeder Contingencies......Page 334
Traditional Engineering and Planning Feeder Systems for Reliability......Page 335
Optimizing Engineering and Planning of Feeder Systems for Reliability......Page 336
Strategic Planning -Analysis and Optimization of the Utility Feeder System's "Strength"......Page 338
Designing a Feeder System to Partly or Fully Support Substation Outages......Page 339
Increasing Feeder Strength to Augment Aging Infrastructures......Page 341
Explicit Distribution Reliability Methods......Page 342
REFERENCES......Page 343
11.1 INTRODUCTION......Page 345
Transformer Aging and Deterioration......Page 346
Routine Transformer Inspection......Page 347
Four Categories of Risk/Recommended Evaluation......Page 348
Thermal Load Tests......Page 351
Electrical tests......Page 353
Tests of ancillary and associated equipment......Page 354
Switchgear......Page 355
Routine inspection......Page 356
Condition evaluation of installed cable......Page 357
Repair and replacement......Page 359
Inspection of Overhead Lines......Page 360
Poles and Pole Assemblies......Page 361
Inspection of Cross-arms, Insulators, Conductors and Hardware......Page 362
Switches and Cutouts......Page 363
Fuses......Page 364
11.6 SERVICE TRANSFORMERS AND SERVICE CIRCUITS......Page 365
Theory of Condition and Correlation with Test Results......Page 366
Condition assessment' predictive capabilities......Page 369
Periodic and Frequency Testing is Required for Efficacy......Page 374
Good Record Keeping......Page 376
REFERENCES......Page 377
Three Activities, But One Decision-Making System......Page 378
12.2 OVERVIEW OF RELIABILITY-CENTERED MAINTENANCE......Page 379
Reliability-Centered Maintenance......Page 381
12.3 BASIC RELIABILITY-CENTERED PRIORITIZATION......Page 383
Reduction in failure rate due to maintenance......Page 384
Obtaining Failure-Rate Reduction Data......Page 387
Prioritization Based on Ranking......Page 388
Changing the Figure of Merit......Page 391
The top projects will be at the top of just about any list......Page 393
What "Reliability Definition" Should A Utility Select?......Page 394
12.4 PRIORITIZATION OF THE TYPE OF MAINTENANCE......Page 395
Application of "intra-project" alternatives evaluation......Page 396
Comprehensive Example Using Intra-Project Optimization......Page 400
Smaller projects are being done......Page 402
Cost and Benefits Should Be Treated as Expectations......Page 403
Use Category-Based Equipment Condition and Maintenance Types......Page 404
Real-World Application Requires a Computerized Approach......Page 407
Multi-District or Multi-Department Application......Page 408
Example of a Much Longer Period of Benefit than Normal Maintenance: Computerized Trouble Call Analysis......Page 411
Example of evaluating very short-term impacts and comparing options for different impact periods: tree-trimming......Page 413
Results are Valid even if Alternatives Cover Different Time Periods......Page 416
Apply Prioritization to All Parts of the System, Not Just One Level or One Department's Venue......Page 417
Use a Reliability Definition as Close as Possible to Regulatory Mandate......Page 418
REFERENCES......Page 419
Aging T&D Infrastructures -> Reliability Optimization......Page 421
What is the Mission?......Page 422
Planning: a Five-Step Process......Page 424
Aging Infrastructure Planning Often Encounters Severe Esthetic and "Fit-In" Constraints......Page 425
Step 3: Identify the Alternatives......Page 426
A common failing: too short a planning horizon......Page 427
Step 4: Evaluating the Alternatives......Page 428
Where mistakes occur in the evaluation step......Page 429
Step 5: Selecting the Best Alternative......Page 430
13.3 SHORT-AND LONG-RANGE PLANNING......Page 431
Long-range Planning: Focus on Reducing Cost......Page 432
The long-range plan does not need great detail......Page 434
Other functions of the long-range plan......Page 435
Handling Uncertainty: Multi-Scenario Planning......Page 436
Uncertainty in T&D growth forecasts cannot be addressed by planning for the expectation of load growth......Page 439
13.4 THE T&D PLANNING PROCESS......Page 441
Spatial forecasts: critical to aging infrastructure planning, particularly when on a tight budget......Page 444
Transmission Planning......Page 447
Substation Planning......Page 451
Feeder system planning......Page 455
Feeder System Planning is a Key Element of Reliability Planning for Aging Infrastructures......Page 456
Short-range feeder planning......Page 457
Customer-Level Planning......Page 458
13.5 THE SYSTEMS APPROACH......Page 460
The Systems Approach Is Important for Aging Infrastructure Planning......Page 463
13.6 SUMMARY OF PLANNING FOR AGING T&D INFRASTRUCTURES......Page 464
REFERENCES......Page 465
14.1 INTRODUCTION......Page 466
Optimal Reliability isn't Necessarily Maximum Reliability......Page 467
14.2 RELIABILITY CAN BE ENGINEERED......Page 468
Results are dependable......Page 470
Using A Reliability Load Flow......Page 471
Engineering the Design Improvements......Page 472
14.3 METHODS FOR DISTRIBUTION SYSTEM RELIABILITY ASSESSMENT......Page 473
Network modeling......Page 474
Markov modeling......Page 475
Monte Carlo simulation......Page 476
Modeling Each Contingency......Page 477
Example Application......Page 480
Performance-Based Industrial Contracts......Page 481
14.5 USE OF A HYBRID ANALYTICAL SIMULATION - MONTE CARLO METHOD TO ANALYZE FINANCIAL RISK......Page 483
Analyzing the Risk from Performance-Based Rates......Page 486
14.6 CONCLUSION AND KEY POINTS......Page 491
REFERENCES AND FURTHER READING......Page 493
First and Foremost, a Power Delivery Company is a Business......Page 495
15.2 THE BUSINESS PERSPECTIVE ON THE PROBLEM......Page 496
Looking for Profits in All the Right Places......Page 497
Impact on Customer Service......Page 499
A Rock and a Hard Place......Page 502
Standards for the Result, Not the Approach......Page 503
Results-Driven Management......Page 505
Quantitative target for results......Page 506
Loop Process of Information and Approval......Page 507
Practical and Effective, but not Trivial to Implement......Page 511
Some departments will be very unhappy......Page 512
15.4 AGING EQUIPMENT AND SYSTEMS - A BUSINESS PERSPECTIVE......Page 513
Optimizing Equipment Value......Page 514
Advanced applications of value/cost optimization......Page 516
Life Extension......Page 518
15.5 CONCLUSION AND SUMMARY......Page 522
REFERENCES......Page 524
16.2 FIVE INTERRELATED FACTORS......Page 525
Number One Recommendation: Implement Cross-Functional and Cross-Departmental Results-Driven Management......Page 528
Implementing RDM......Page 529
Some departments will be very unhappy......Page 530
Voltage Reduction on the Primary Distribution System......Page 531
Adopt Reliability-Based Planning and Engineering Methods......Page 533
Optimize Against PBR Rules......Page 534
Utility Efforts under PBR should be directed at Two Goals......Page 535
IT Should Focus on Customer Service......Page 537
Transformer-Load Management System......Page 539
Extending TLM to include performance management of service......Page 540
Optimize Equipment Loading to Provide Maximum Value......Page 541
Cost of good solutions is not high......Page 546
REFERENCES......Page 547